Single phase alternating current motor



Nov. 2, 1937. s. SEITNER 2,097,577

I S INGLE PHASE ALTERNATING CURRENT MOTOR Filed Sept. 19, 1956 o"STARTING AND DIRECTION OF ROTATION CONTROLLED 1' BY CLOSURE OF ONE ORTHE OTHER RING CIRCUIT" 7 Sebastian sei'tn er, b COJDQQ-HKQLYMMIWPatented Nov. 2, 1937 UNITED STATES PATENT OFFICE 2,097,577 SINGLE PHASEALTERNATING CURRENT MOTOR Sebastian Seitner, Alzey, Germany, assignor tofirm: Markes & 00.,

Gesellschaft mit beschrankter Haftung, Ludenscheid, Germany ApplicationSeptember 19, 1936, Serial No. 101,653 In Germany April 3, 1934 1 Claim.

This invention relates to improvements in single phase alternatingcurrent motors which comprise an additional secondary winding foruninterruptedly supplying consumers with current 5 of reduced voltage.

It is known that small consumers can be supplied with current of areduced voltage compared with the voltage of the supply mains by using,.

instead of a transformer, a current supply obtained from a separateadditional winding of an electric motor.

The present invention relates to a motor, the rotor of which can bestopped while at the same time maintaining the current supply to small 7consumers. According to the invention a single phase alternating currentmotor having, according to the divided pole principle, short-circuitablerings or pole shading windings on its poles for determining and/orreversing the direction of rota tion and having stators which carry atleast two differentially connected exciting windings for alternatingcurrent arranged on' diflerent yoke sides but adjacent to the samepole,is. provided with an additional secondary winding which is arranged onone of the pole arms, the rotor capable of being arrested whilenevertheless maintaining the current supplied by the. secondarywinding,- by disconnecting one of the exciting coils or one of thegroups of exciting coils.

A motor constructed according to the invention can thus be used eitheras a squirrel cage motor or as a transformer or, if desired, for bothpurposes simultaneously. These advantages entail a useful and economicalapplication of the motor for driving machinery, which has to rotate ineither sense and where by dint of the available switches the low tensioncurrent produced can. be used at the same time forthe illumination ofmoist premises or premises containing inflammable material, as lowtension currents are not dangerous to human life. Similar conditionsarise.in driving the'machining used for bakeries or for the manufactureof confectionery,'where the switch arrangement makes possible the op- 45tional use of the low tension current for the illumination of the ovens.In this case the motor having a short circuited rotor oifers thecombination of a source of power and a transformer which r providescurrent of a safe voltage. This combinationalso increases the totalefliciency of such an installation, because only a single magnetizingcurrent is required. The power factor of the motor is thus improved andthe low tension current can be used without substantially increasing 5the total current taken by the machine.

The invention will be more readily understood by means of theaccompanying drawing, in which:

Figure 1 shows the circuit diagram of a machine for single phasealternating current with a short-circuited rotor when usedsimultaneously 5 as a driving motor and as a transformer. Fig. 2 is adiagram of the machine when the-rotor is at rest and the machine isoperating solely as a transformer.

Referring first to Fig. 1 the followingwill make 10 the invention clear.,The current supplied by the mains la flows to the terminals i and a.and thus simultaneously to the coil 2 and through switch I and terminals9 and l0,to the coil 8. The two coils produce magnetic fluxes inoppositedirections in the magnetic core b, a; a, c which meet at the pole-piecesd and -e and flow through the rotor l5. I

A switch I is provided whereby therotor can be stopped and started. If,as shown in Fig. 2, 20

current is induced in the additional coil 4 both 30 when the rotor is atrestand when it is running, the low tension of the said coilcorresponding to the number of turns used. As a result of this ar-'rangement the stator acts as a transformer. The low tension current istaken oil? at the terminals 5 and 6. It'is not influenced by operatingthe 1 switch I. t

At the pole-pieces the magnetic fluxes are displaced in respect of theirphase in known manner by means of pole-shading conductors orshortcircuitable rings, the resultant lagging flux of which produces therotation of the armature. pole-pieces may be imagined to consist ofthree parts. The pole-shading coils or rings ii, I2, i3 and M arearranged on the exterior. pairs of coils or rings which are respectivelydis placed by180", for instance ii and I or I 2 and l3, may beshort-circuited as desired and the rotor is thus driven clockwise orcounterclockwise.

This control and mode of'connection can be 50 applied alsoto multipolarmachinery.

The'operation of the machine is believed to be clear from the abovedescription, but it may be briefly summarized as follows:

Current supplied from the mains la to'the The.

The said I statorcoiisl an linparsllelwilltraverse theseooilsinsuchdirectionastoprodueeopposing alternating fluxu in'the legs I!and c olthe yoke or core, which will 9 sinthearmscandofoitheyokeatcandmrespectively, where such iiuxesmusttraverse the rotor ll andthesurrwndinsairgaps. Dueto theshort-circuitable rings l2, I! or i I, is, whichever pair isshort-circuited. the rotor will he set into rotation due to the phasedisplacements produeed by the shaded portions oi the respective polepieces. It is thus possible to cause the rotor to turn either clockwiseor counterclockwiseby short-circulting the corresponding rings.

However, when the switch I is opened, power is no longer supplied to'thewinding I, while winding 2 continues to receive such power. Since thereis thus no opposing magne -motive iorce produced by the winding I theflux produced by the winding I has a path oi'low magnetic reluctanceprovided by theyoke 'or core I), a, c, 0'. Since this path hasvno airgaps therein its reluctance is much lower than the parallel path.through the rotor and the two air gaps in series 25 with the rotor. sothat only a negligible amount oi flux will flow when the coil I isn'ot'energised. this man leakage flux being insuiiicient to operatethe'giotor.

However. in either that is, whether the 30 main flux is produced'h'ycoil I alone or by coils 2 and l Jointly. the yoke arm it upon which arelocated windings I and 4 will always constitute a transformer whereincoil 2 is the primary wind-' ing and coil 4 the secondary winding, sothat res ammo" v gardle'ssot whether or not the deviceis also operatingas a motor, the transformer action dependent solely upon the core b andthe windings I and 4 will not be materially aflected and the coil 4will, therefore, at all times, deliver a supply of alternating currentat substantially constant reduced potential, derived from the powersupplied to the coil I.

The present invention may conveniently be used alsoin connection withtoy-cinema g ph apparatus as well as for toy-railways provided withlight, electrically driven toy motor cars provlded with light, andsimilar toys.

WhatIclaim anddesiretosecurebyletteu Patent in the United States is:

Single phase alternating current motor oi the.

split pole type with a short-circuited rotor, comprising. a statorhaving at least two yokesides and intermediate iield poles, at least twopairs of short-circuitable rings on the poles ior. reversing thedirection oi rotation, at-ieast two exciting windings for alteratingcurrent electrically in parallel and in opposing flux connection ondifferent yoke-sides adjacent to the same stator pole, an additionalsecondary winding for supplying external consumers with reduced ten-"sion current on one yoke-side and means for sen,-

arately disconnecting the exciting winding ar-i ranged on theotheryoke-side to stop the rotor while maintaining the samereducedvoltage at the secondary winding as during the running oi the rotor.

